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Mok, W.Y.

Paper Title Page
TH6REP032 Fast-Gated Camera Measurements in SPEAR3 4015
 
  • W.X. Cheng, W.J. Corbett, A.S. Fisher, X. Huang, J.A. Safranek, A. Terebilo
    SLAC, Menlo Park, California
  • W.Y. Mok
    Life Imaging Technology, Palo Alto, California
 
 

Funding: Work sponsored by U.S. Department of Energy Contract DE-AC03-76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences.


An intensified, fast-gated CCD camera was recently installed on the visible diagnostic beam line in SPEAR3. The ~2nS electronic gate capability, ability to make multiple-exposure images and to acquire sequences of images provides good diagnostic potential. Furthermore, the addition of a rotating mirror just upstream of the photocathode provides the ability to optically ‘streak’ multiple images across the photocathode. In this paper, we report on several fast-gated camera studies including (1) resonant excitation of vertical bunch motion, (2) imaging of the injected beam with and without emittance-spoiling windows in the upstream transfer line, (3) injection kicker tuning to minimize perturbations to the stored beam and (4) images of short-bunch ‘bursting’ in the low momentum-compaction mode of operation.

 
TH6REP033 Interferometer Beam Size Measurements in SPEAR3 4018
 
  • W.J. Corbett, W.X. Cheng, A.S. Fisher, E. Irish
    SLAC, Menlo Park, California
  • T.M. Mitsuhashi
    KEK, Ibaraki
  • W.Y. Mok
    Life Imaging Technology, Palo Alto, California
 
 

Funding: Work sponsored by U.S. Department of Energy Contract DE-AC03-76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences.


A two-slit interferometer has been installed in the SPEAR3 diagnostic beam line to measure vertical beam size at a dipole source point. The diagnostic beam line accepts unfocused, visible light in a 3.5 x 6.0 mrad aperture so that at the slit location 17 m from the source, the vertical extent of the beam is 100mm. For typical source sizes of sigy~15 um (0.1% emittance coupling) a slit separation of 80 mm produces fringe visibility of order V=0.5. Hence a significant plot of fringe visibility vs. slit separation can be generated to infer source size via Fourier transformation. In this paper we report on the interferometer construction, beam size measurement and potential deficiencies of the system, and compare with theoretical results.